International 10-20 system

Anterior-Posterior Bipolar Montage

Common Average Reference Montage

Common EEG Pattern

  1. Eye Blink

Bell’s phenomenon -> large

  1. Alpha rhythm : 10 Hz

  2. Focal Epileptiform Discharges

Diagnoistic Yield

2 major determinants of detecting scalp abnormality:

  1. Area of cortex involved : In general, 10-20 cm^2 of cortex must be involved to be detected on scalp eeg.
  2. Location : If deeper cortex is invelved, abnormality is harder to be detected.

Polarity Rules

The differential amplifier : 2 input -> 1 output as difference.